Practical TIG Welding: 2T and 4T Mode
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2T and 4T Mode
03.20
| 00:00 | - We've already touched briefly on the 2T and 4T settings in a previous module but here we're going to go into a little more detail. |
| 00:07 | These settings define how the welder will respond to the trigger on the torch and they're not relevant if you're using a foot pedal instead. |
| 00:15 | Let's start with the 2T setting which means that you need to press down and hold the trigger for the duration of the weld. |
| 00:21 | If you have set the upslope and downslope settings to 0 then the torch will arc straight up to your maximum set weld amps as soon as you press the trigger, and stay there as long as the trigger is held. |
| 00:33 | Likewise, as soon as you let go of the trigger, the arc will terminate instantly. |
| 00:38 | This setting in particularly useful when trying to put a tack on something to hold two pieces of material together. |
| 00:44 | If you have upslope and downslope settings when on 2T mode, then the machine will initiate your upslope cycle when the trigger is pressed. |
| 00:53 | The same applies when you let go of the trigger, it will start to initiate the downslope cycle. |
| 00:59 | For example, if you have a 4 second downslope setting, when you let go of the trigger, then the machine will slowly taper off the amperage over 4 seconds until it reaches your base amps and then terminates. |
| 01:10 | This is important to keep in mind because the arc will not instantly terminate when we release the trigger and you need to consider this when you're finishing your weld. |
| 01:20 | We will find that we use these 2T settings the most when learning as it will give us a sense of more control over our weld. |
| 01:27 | As we advance with our TIG welding skills however, we'll start to see the potential benefits of the 4T mode. |
| 01:34 | This 4T mode means that we need to press the trigger to initiate the arc but we do not need to hold it down for the duration of the weld. |
| 01:44 | The machine will continue at the maximum set amps until you press the trigger again to terminate the arc. |
| 01:50 | This can become confusing when using 4T with upslope and downslope settings though. |
| 01:55 | If this is the case, when we press and hold the trigger down, the machine will only give us the start amps that we've set. |
| 02:03 | Once we let go of the trigger, then the upslope cycle will begin. |
| 02:07 | The same applies when we get to the end of the weld, pressing the trigger will initiate the downslope cycle, however if we hold the trigger down, the machine will remain at the end amps setting until we release the trigger again. |
| 02:20 | Note that there are subtle differences from one machine to another in how the 4T settings are applied, relative to the application of the trigger but this is a typical example of the operation. |
| 02:31 | The 4T mode is useful when we've mastered it as it means that we don't need to be holding the trigger the whole time if we're doing long weld passes. |
| 02:41 | This allows our hand to be more relaxed and this can help produce more consistent welds. |
| 02:45 | Another benefit of the 4T setting is if we find ourselves welding in a dark corner or inside a vessel or tank where it may be difficult to properly see the seam we want to weld. |
| 02:57 | Holding down the trigger will arc up the torch to our start amps which are usually very low. |
| 03:02 | Perhaps only 10 amps for example. |
| 03:04 | This will illuminate the workpiece, allowing us to see and we can then keep the trigger held down until we're happy that our arc is exactly where we want it. |
| 03:13 | When comfortable we can let go of the trigger and begin the welding process. |
